Communication method based on a CU-DU architecture

ABSTRACT

This application provides a communication method and a communication system. A central unit (CU) obtains a quality of service (QoS) parameter of a QoS data flow and performs mapping the QoS data flow to a bearer based on the QoS parameter of the QoS data flow. The CU determines a QoS parameter of the bearer based on the QoS parameter of the QoS data flow and sends a context setup request message to a distributed unit (DU), wherein the context setup request message comprises the QoS parameter of the bearer, the QoS parameter of the QoS data flow and the mapping relationship between the QoS data flow and the bearer.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of International Application No.PCT/CN2018/085605, filed on May 4, 2018, which claims priority toChinese Patent Application No. 201710314208.4, filed on May 5, 2017. Thedisclosures of the aforementioned applications are hereby incorporatedby reference in their entireties.

TECHNICAL FIELD

This application relates to the communications field, and morespecifically, to a communication method, a base station, and a terminaldevice.

BACKGROUND

A concept of separating distributed unit (DU) from central unit (CU) isintroduced in 5th Generation (5G) communications system. To be specific,a base station is divided into two parts: CU and DU.

SUMMARY

This application provides a communication method, a base station, and aterminal device, so that a DU can schedule a bearer based on a QoSparameter of the bearer.

According to a first aspect, a communication method is provided. Themethod includes: obtaining, by a central unit CU, a quality of serviceQoS parameter of a QoS data flow; determining, by the CU, mappinginformation between the QoS data flow and a bearer based on the QoSparameter of the QoS data flow; determining, by the CU, a QoS parameterof the bearer based on the QoS parameter of the QoS data flow; andsending, by the CU, the QoS parameter of the bearer to a distributedunit DU.

In this application, the CU determines the QoS parameter of the bearerand a mapping relationship between the QoS data flow and the bear. Thisconforms to a CU-DU function division trend. To be specific, both theQoS parameter of the bearer and the mapping relationship between the QoSdata flow and the bear are determined at a service data adaptationprotocol (SDAP) layer of the CU. This can keep consistency between thebearer and the QoS parameter of the bearer to the greatest extent, andhelps the DU schedule the bearer based on the QoS parameter of thebearer.

With reference to the first aspect, in some implementations of the firstaspect, the determining, by the CU, mapping information between the QoSdata flow and a bearer based on the QoS parameter of the QoS data flowincludes: determining, by the CU, the mapping information between theQoS data flow and the bearer by performing comparison on the QoSparameter of the QoS data flow.

For example, QoS data flows that have relatively similar QoS parametersmay be mapped to a same bearer.

With reference to the first aspect, in some implementations of the firstaspect, there is a mapping relationship between a first bearer and aplurality of data flows in the QoS data flow, and the determining, bythe CU, a QoS parameter of the bearer based on the QoS parameter of theQoS data flow includes: selecting, by the CU, a QoS parameter of thefirst bearer from QoS parameters of the plurality of data flows; orcalculating, by the CU, a QoS parameter of the first bearer based on QoSparameters of the plurality of data flows.

With reference to the first aspect, in some implementations of the firstaspect, the sending, by the CU, the QoS parameter of the bearer to a DUincludes: sending, by the CU, a first message to the DU, where the firstmessage includes the QoS parameter of the bearer, and the first messageis a bearer setup request message or a context setup request message.

With reference to the first aspect, in some implementations of the firstaspect, the CU sends a bearer modification message to the DU, where thebearer modification message includes at least one of first informationand second information, the first information is a modified QoSparameter of the bearer, and the second information is used to add a QoSdata flow to the bearer or remove a QoS data flow from the bearer.

With reference to the first aspect, in some implementations of the firstaspect, the determining, by the CU, mapping information between the QoSdata flow and a bearer based on the QoS parameter of the QoS data flowincludes: determining, by the CU at a Service Data Adaptation ProtocolSDAP layer, the mapping information between the QoS data flow and thebearer.

With reference to the first aspect, in some implementations of the firstaspect, the method further includes: obtaining, by the CU, anon-QoS-data-flow-level QoS parameter, where the non-QoS-data-flow-levelQoS parameter includes any one of or a combination of a slice-level QoSparameter, a user equipment (UE)-level QoS parameter, and a packet dataunit (PDU) session-level QoS parameter, and sending, by the CU, thenon-QoS-data-flow-level QoS parameter to the DU; or obtaining, by theCU, a non-QoS-data-flow-level QoS parameter, where thenon-QoS-data-flow-level QoS parameter includes any one of a slice-levelQoS parameter, a UE-level QoS parameter, and a packet data unit PDUsession-level QoS parameter, and controlling, by the CU, correspondingdata transmission based on the non-QoS-data-flow-level QoS parameter.

According to a second aspect, a communication method is provided. Themethod includes: obtaining, by a central unit CU, a quality of serviceQoS parameter of a QoS data flow; determining, by the CU, mappinginformation between the QoS data flow and a bearer based on the QoSparameter of the QoS data flow; and sending, by the CU to a distributedunit DU, the QoS parameter of the QoS data flow and the mappinginformation between the QoS data flow and the bearer.

In this application, the DU can flexibly schedule the bearer based onthe QoS parameter of the QoS data flow and the mapping informationbetween the QoS data flow and the bearer. For example, a medium accesscontrol (MAC) layer of the DU can flexibly schedule the bearer based oninformation such as load, the QoS parameter of the QoS data flow, andthe mapping information between the QoS data flow and the bearer.

With reference to the second aspect, in some implementations of thesecond aspect, the determining, by the CU, mapping information betweenthe QoS data flow and a bearer based on the QoS parameter of the QoSdata flow includes: determining, by the CU, the mapping informationbetween the QoS data flow and the bearer by performing comparison on theQoS parameter of the QoS data flow.

With reference to the second aspect, in some implementations of thesecond aspect, the sending, by the CU to a DU, the QoS parameter of theQoS data flow and the mapping information between the QoS data flow andthe bearer includes: sending, by the CU, a first message to the DU,where the first message includes the QoS parameter of the QoS data flowand the mapping information between the QoS data flow and the bearer,and the first message is a bearer setup request message or a contextsetup request message.

With reference to the second aspect, in some implementations of thesecond aspect, the method further includes: sending, by the CU, a bearermodification message to the DU, where the bearer modification messageincludes at least one of first information and second information, thefirst information is a modified QoS parameter of the bearer, and thesecond information is used to add a QoS data flow to the bearer orremove a QoS data flow from the bearer.

With reference to the second aspect, in some implementations of thesecond aspect, the determining, by the CU, mapping information betweenthe QoS data flow and a bearer based on the QoS parameter of the QoSdata flow includes: determining, by the CU at a Service Data AdaptationProtocol SDAP layer, the mapping information between the QoS data flowand the bearer.

With reference to the second aspect, in some implementations of thesecond aspect, the method further includes: obtaining, by the CU, anon-QoS-data-flow-level QoS parameter, where the non-QoS-data-flow-levelQoS parameter includes any one of or a combination of a slice-level QoSparameter, a UE-level QoS parameter, and a packet data unit PDUsession-level QoS parameter, and sending, by the CU, thenon-QoS-data-flow-level QoS parameter to the DU; or obtaining, by theCU, a non-QoS-data-flow-level QoS parameter, where thenon-QoS-data-flow-level QoS parameter includes any one of a slice-levelQoS parameter, a UE-level QoS parameter, and a packet data unit PDUsession-level QoS parameter, and controlling, by the CU, correspondingdata transmission based on the non-QoS-data-flow-level QoS parameter.

According to a third aspect, a communication method is provided. Themethod includes: receiving, by a distributed unit DU, a QoS parameter ofa bearer that is sent by a central unit CU, where the bearer is a bearerthat is determined by the CU based on a QoS parameter of a QoS data flowand that has a mapping relationship with the QoS data flow, and the QoSparameter of the bearer is determined by the CU based on the QoSparameter of the QoS data flow; and scheduling, by the DU, the bearerbased on the QoS parameter of the bearer.

In this application, the CU determines the QoS parameter of the bearerand the mapping relationship between the QoS data flow and the bear.This conforms to a CU-DU function division trend. To be specific, boththe QoS parameter of the bearer and the mapping relationship between theQoS data flow and the bear are determined at an SDAP layer of the CU.This can keep consistency between the bearer and the QoS parameter ofthe bearer to the greatest extent, and helps the DU schedule the bearerbased on the QoS parameter of the bearer.

With reference to the third aspect, in some implementations of the thirdaspect, the mapping information is determined by the CU by performingcomparison on the QoS parameter of the QoS data flow.

With reference to the third aspect, in some implementations of the thirdaspect, the receiving, by a DU, a QoS parameter of a bearer that is sentby a CU includes: receiving, by the DU, a first message sent by the CU,where the first message includes the QoS parameter of the bearer, andthe first message is a bearer setup request message or a context setuprequest message.

With reference to the third aspect, in some implementations of the thirdaspect, the method further includes: receiving, by the DU, a bearermodification message sent by the CU, where the bearer modificationmessage includes at least one of first information and secondinformation, the first information is a modified QoS parameter of thebearer, and the second information is used to add a QoS data flow to thebearer or remove a QoS data flow from the bearer.

With reference to the third aspect, in some implementations of the thirdaspect, the mapping information between the QoS data flow and the beareris determined by the CU at a Service Data Adaptation Protocol SDAPlayer.

With reference to the third aspect, in some implementations of the thirdaspect, the method further includes: receiving, by the DU, anon-QoS-data-flow-level QoS parameter sent by the CU, where thenon-QoS-data-flow-level QoS parameter includes any one of or acombination of a slice-level QoS parameter, a UE-level QoS parameter,and a packet data unit PDU session-level QoS parameter; and controlling,by the DU, corresponding data transmission based on thenon-QoS-data-flow-level QoS parameter.

According to a fourth aspect, a communication method is provided. Themethod includes: receiving, by a distributed unit DU, a QoS parameter ofa QoS data flow and mapping information between the QoS data flow and abearer, where the QoS parameter of the QoS data flow and the mappinginformation are sent by a central unit CU; and scheduling, by the DU,the bearer based on the QoS parameter of the QoS data flow and themapping information between the QoS data flow and the bearer.

In this application, the DU can flexibly schedule the bearer based onthe QoS parameter of the QoS data flow and the mapping informationbetween the QoS data flow and the bearer. For example, a MAC layer ofthe DU can flexibly schedule the bearer based on information such asload, the QoS parameter of the QoS data flow, and the mappinginformation between the QoS data flow and the bearer.

With reference to the fourth aspect, in some implementations of thefourth aspect, the mapping information is determined by the CU byperforming comparison on the QoS parameter of the QoS data flow.

With reference to the fourth aspect, in some implementations of thefourth aspect, there is a mapping relationship between the bearer and aplurality of data flows in the QoS data flow, and a QoS parameter of thebearer is selected by the CU from QoS parameters of the plurality ofdata flows, or a QoS parameter of the bearer is obtained by the CUthrough calculation based on QoS parameters of the plurality of dataflows.

With reference to the fourth aspect, in some implementations of thefourth aspect, the receiving, by a DU, a QoS parameter of a QoS dataflow and mapping information between the QoS data flow and the bearer,where the QoS parameter of the QoS data flow and the mapping informationare sent by a CU includes: receiving, by the DU, a first message sent bythe CU, where the first message includes the QoS parameter of the bearerand the mapping information between the QoS data flow and the bearer,and the first message is a bearer setup request message or a contextsetup request message.

With reference to the fourth aspect, in some implementations of thefourth aspect, the method further includes: receiving, by the DU, abearer modification message sent by the CU, where the bearermodification message includes at least one of first information andsecond information, the first information is a modified QoS parameter ofthe bearer, and the second information is used to add a QoS data flow tothe bearer or remove a QoS data flow from the bearer.

With reference to the fourth aspect, in some implementations of thefourth aspect, the mapping information between the QoS data flow and thebearer is determined by the CU at a Service Data Adaptation ProtocolSDAP layer.

With reference to the fourth aspect, in some implementations of thefourth aspect, the method further includes: receiving, by the DU, anon-QoS-data-flow-level QoS parameter sent by the CU, where thenon-QoS-data-flow-level QoS parameter includes any one of or acombination of a slice-level QoS parameter, a UE-level QoS parameter,and a packet data unit PDU session-level QoS parameter; and controlling,by the DU, corresponding data transmission based on thenon-QoS-data-flow-level QoS parameter.

According to a fifth aspect, a communication method is provided. Themethod includes: obtaining, by UE, mapping information between a QoSdata flow and a bearer, where the mapping information is determined by aCU based on a QoS parameter of the QoS data flow; and sending, by theUE, uplink data to a DU based on a mapping relationship between the QoSdata flow and the bearer.

In this application, the mapping information between the QoS data flowand the bearer, based on which the UE transmits the uplink data, isdetermined by the CU based on the QoS parameter of the QoS data flow.This conforms to a CU-DU function division trend, and can ensure aneffect of transmitting the uplink data by the UE.

With reference to the fifth aspect, in some implementations of the fifthaspect, the obtaining, by the UE, mapping information between a QoS dataflow and a bearer includes: receiving, by the UE, a Radio ResourceControl connection reconfiguration message sent by the DU; andobtaining, by the UE, the mapping relationship between the QoS data flowand the bearer from the Radio Resource Control connectionreconfiguration message.

With reference to the fifth aspect, in some implementations of the fifthaspect, the UE receives a bearer modification message sent by the DU,where the bearer modification message includes at least one of firstinformation and second information, the first information is a modifiedQoS parameter of the bearer, and the second information is used to add aQoS data flow to the bearer or remove a QoS data flow from the bearer;the UE determines the QoS parameter of the bearer based on the bearermodification message; and/or the UE adds a QoS data flow to the beareror removes a QoS data flow from the bearer based on the bearermodification message.

According to a sixth aspect, a base station is provided. The basestation includes a CU, and the CU includes modules configured to performthe method according to any one of the first aspect or theimplementations of the first aspect.

According to a seventh aspect, a base station is provided. The basestation includes a CU, and the CU includes modules configured to performthe method according to any one of the second aspect or theimplementations of the second aspect.

According to an eighth aspect, a base station is provided. The basestation includes a DU, and the DU includes modules configured to performthe method according to any one of the third aspect or theimplementations of the third aspect.

According to a ninth aspect, a base station is provided. The basestation includes a DU, and the DU includes modules configured to performthe method according to any one of the fourth aspect or theimplementations of the fourth aspect.

According to a tenth aspect, a terminal device is provided. The terminaldevice includes modules configured to perform the method according toany one of the fifth aspect or the implementations of the fifth aspect.

According to an eleventh aspect, a communications apparatus is provided.The apparatus includes: a storage medium and a processor. The storagemedium stores a computer executable program. The processor is connectedto the storage medium, and executes the computer executable program toimplement the method according to any one of the first aspect to thefifth aspect, or the implementations of the first aspect to the fifthaspect, or implement a part, in the method, that can be implemented bythe processor.

The storage medium may be a nonvolatile storage medium.

According to a twelfth aspect, a computer readable medium is provided.The computer readable medium stores program code to be executed by acomputer. The program code includes an instruction used to perform themethod according to any one of the first aspect to the fifth aspect, orthe implementations of the first aspect to the fifth aspect.

DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic flowchart of a communication method according toan embodiment of this application;

FIG. 2 is a schematic flowchart of a communication method according toan embodiment of this application;

FIG. 3 is a schematic diagram of a scenario in which UE is handed overfrom a current base station to a target base station;

FIG. 4 is a schematic diagram of a scenario in which UE is handed overfrom a current DU of a base station to a target DU;

FIG. 5 is a schematic diagram of a scenario in which UE is handed overfrom a DU of a primary base station to a DU of a secondary base station;

FIG. 6 is a schematic flowchart of a communication method according toan embodiment of this application;

FIG. 7 is a schematic flowchart of a communication method according toan embodiment of this application;

FIG. 8 is a schematic flowchart of a communication method according toan embodiment of this application;

FIG. 9 is a schematic flowchart of a communication method according toan embodiment of this application;

FIG. 10A and FIG. 10B are a flowchart of a communication methodaccording to an embodiment of this application;

FIG. 11A and FIG. 11B are a flowchart of a communication methodaccording to an embodiment of this application;

FIG. 12 is a flowchart of a communication method according to anembodiment of this application;

FIG. 13 is a flowchart of a communication method according to anembodiment of this application;

FIG. 14 is a schematic block diagram of a base station according to anembodiment of this application;

FIG. 15 is a schematic block diagram of a base station according to anembodiment of this application;

FIG. 16 is a schematic block diagram of a base station according to anembodiment of this application;

FIG. 17 is a schematic block diagram of a base station according to anembodiment of this application;

FIG. 18 is a schematic block diagram of a terminal device according toan embodiment of this application; and

FIG. 19 is a schematic block diagram of a communications apparatusaccording to an embodiment of this application.

DESCRIPTION OF EMBODIMENTS

The following describes technical solutions of this application withreference to accompanying drawings.

The technical solutions of this application may be applied to acommunications system using a CU-DU separation design, or acommunications system having a similar design principle, for example, aLong Term Evolution (LTE) system, a 5th Generation (5G) communicationssystem, or another communications system to which a CU-DU separationarchitecture is applicable.

This application relates to a terminal device. The terminal device maybe a device that includes a radio sending/receiving function and thatmay cooperate with a network device to provide a communication servicefor a user. The terminal device may be referred to as user equipment(UE), an access terminal, a subscriber unit, a subscriber station, amobile station, a mobile console, a remote station, a remote terminal, amobile device, a user terminal, a terminal, or the like. A specificrepresentation form of the terminal device may be an intelligentterminal, a personal digital assistant (PDA), a handheld device having awireless communication function, an Internet of Things device, anin-vehicle device, a wearable device, or the like.

It may be understood that there are different service scenarios in acommunications network, and a terminal device may be in correspondingforms in different service scenarios. This is not limited in thisapplication.

For example, 5G includes three typical service scenarios.

A first scenario is enhanced mobile broadband. In this applicationscenario, a peak network access rate for an intelligent terminal userneeds to reach 10 Gbps or even 20 Gbps, to provide support forhigh-bandwidth applications such as virtual reality, ubiquitous videoon-live and sharing, and anytime and anywhere cloud access. A secondscenario is big-connection Internet of Things. In this scenario, a 5Gnetwork needs to support 1,000,000 human-things connections per squarekilometer.

A third scenario is ultra-reliable and low latency communications. Inthis scenario, a latency of a 5G network is required to reach 1millisecond, to provide strong support for low-latency services such asintelligent manufacturing, remote mechanical control, driver assistance,and automatic driving.

FIG. 1 is a flowchart of a communication method 100 according to anembodiment of this application. Specific steps of the communicationmethod 100 are as follows.

110. A CU obtains a QoS parameter of a QoS data flow.

This step has different implementations. Specific examples are asfollows.

Manner 1:

The CU first receives a QoS data flow sent by a core network, and thenobtains a QoS parameter of the QoS data flow.

Specifically, a user plane packet header of the QoS data flow includes aQoS data flow identifier (ID), and there is a correspondence between theQoS data flow ID and the QoS parameter of the QoS data flow.

Based on this, the CU can determine the QoS parameter of the QoS dataflow based on the QoS data flow ID and the correspondence between theQoS data flow ID and the QoS parameter of the QoS data flow.

The correspondence between the QoS data flow ID and the QoS parameter ofthe QoS data flow may be preset on the CU, or may be provided by thecore network. If the correspondence between the QoS data flow ID and theQoS parameter of the QoS data flow is provided by the core network, theCU may obtain the correspondence between the QoS data flow ID and theQoS parameter of the QoS data flow from a protocol data unit (PDU)session setup request sent by the core network.

Manner 2:

When the CU does not receive a QoS data flow sent by a core network, theCU may also obtain a QoS parameter of the QoS data flow.

For example, the CU obtains, from a PDU session setup request sent bythe core network, a QoS data flow ID and a correspondence between theQoS data flow ID and the QoS parameter, so as to determine the QoSparameter of the QoS data flow based on the QoS data flow ID and thecorrespondence between the QoS data flow ID and the QoS parameter.

The QoS parameter of the QoS data flow may include the followingparameters:

(1) 5G QoS class identifier (5QI);

(2) allocation and retention priority (ARP);

(3) guaranteed flow bit rate (GFBR); and

(4) maximum flow bit rate (MFBR).

The 5QI may specifically include: guaranteed bit rate (GBR) ornon-guaranteed bit rate (non-GBR) type information, a priority level, apacket delay budget, and a packet error rate.

120. The CU determines mapping information between the QoS data flow anda bearer based on the QoS parameter of the QoS data flow.

The bearer may be a data radio bearer (DRB) or a radio bearer (RB).Specifically, a bearer between the CU and a DU may be an RB, and abearer between the DU and UE may be a DRB.

It should be understood that the QoS data flow may include a pluralityof data flows, and the bearer may also include a plurality of bearers. Amapping relationship, determined by the CU, between the QoS data flowand the bearer may be that a plurality of data flows are mapped to aplurality of bearers. In addition, different data flows may be mapped toone bearer, and one bearer may include one or more data flows.

With reference to specific examples, the following describes determiningof the mapping relationship between the QoS data flow and the bearerbased on the QoS parameter of the QoS data flow.

During the determining of the mapping relationship between the QoS dataflow and the bearer, QoS data flows that have relatively similar QoSparameters may be mapped to a same bearer, and QoS data flows that havegreatly different QoS parameters may be mapped to different bearers.

It should be understood that when the CU determines the mappingrelationship between the QoS data flow and the bearer, the CU mayspecifically map the QoS data flow to the bearer at a service dataadaptation protocol (SDAP) layer of the CU.

For example, the QoS data flow includes a first data flow, a second dataflow, and a third data flow; the bearer includes a first bearer and asecond bearer; and QoS parameters of the first data flow, the seconddata flow, and the third data flow are shown in Table 1. In Table 1,parameters of the first data flow and the second data flow arerelatively similar (where packet error rates of the two data flows arethe same, and packet delay budgets and priority levels are alsosimilar). However, parameters of the third data flow are greatlydifferent from the parameters of the first data flow and the second dataflow. Therefore, during the determining of the mapping relationshipbetween the QoS data flow and the bearer, a mapping relationship shownin Table 2 may be obtained, where the first data flow and the seconddata flow are mapped to the first bearer, and the third data flow ismapped to the second bearer.

TABLE 1 QoS parameter QoS QoS parameter of the first parameter of the ofthe Parameter type data flow second data flow third data flow GBR ornon-GBR Non-GBR Non-GBR GBR type information Priority level 3 4 6 Packetdelay budget 200 ms 210 ms 300 ms Packet error rate 0.00001 0.000010.00001

TABLE 2 QoS data flow Mapped-to bearer First data flow First bearerSecond data flow Third data flow Second bearer

It should be understood that Table 1 and Table 2 are merely used asexamples herein to describe the determining of the mapping relationshipbetween the QoS data flow and the bearer. Essentially, during thedetermining of the mapping relationship between the QoS data flow andthe bearer, a main QoS parameter of the QoS data flow may be flexiblyselected based on different application scenarios, so as to determinethe mapping relationship between the QoS data flow and the bearer. Forexample, in an ultra-reliable and low latency communications scenario,if packet delay budgets of two QoS data flows are the same or relativelysimilar, the two QoS data flows may be mapped to one bearer. Inaddition, usually, when the CU determines the mapping relationshipbetween the QoS data flow and the bearer, the CU may map a GBR-type dataflow and a non-GBR-type QoS data flow to different bearers.

It should be understood that the mapping relationship between the QoSdata flow and the bearer may be determined depending on whether the QoSparameters of the QoS data flows are the same or based on a degree ofsimilarity between the QoS parameters of the QoS data flows, or may bedetermined based on another relationship between the QoS data flows (forexample, whether the QoS data flows belong to a same session).

Further, the first data flow and the second data flow may be in a samePDU session, and the third data flow is in another PDU session.Specifically, as shown in Table 3, a first PDU session includes thefirst data flow and the second data flow, and a second PDU sessionincludes the third data flow. It can be learned from Table 3 that dataflows in different PDU sessions are corresponding to different bearers,the data flows in the first PDU session are mapped to the first bearer,and the data flow in the second PDU session is mapped to the secondbearer.

TABLE 3 PDU session QoS data flow Mapped-to bearer First PDU sessionFirst data flow First bearer Second data flow Second PDU session Thirddata flow Second bearer

After determining the mapping relationship between the QoS data flow andthe bearer, the CU may map the QoS data flow to the bearer based on theQoS parameter of the QoS data flow. The mapping, by the CU, the QoS dataflow to the bearer may be specifically: mapping the QoS data flow to thebearer at the Service Data Adaptation Protocol (SDAP) layer of the CU.

130. The CU determines a QoS parameter of the bearer based on the QoSparameter of the QoS data flow.

It should be understood that the CU may determine the QoS parameter ofthe bearer based on the QoS parameter of the QoS data flow whendetermining the mapping relationship between the QoS data flow and thebearer; or the CU may determine the QoS parameter of the bearer based onthe QoS parameter of the QoS data flow after determining the mappingrelationship between the QoS data flow and the bearer.

A specific form of the QoS parameter of the bearer may be shown in Table4.

TABLE 4 Bearer   > Identifier of the bearer > QoS parameter of thebearer

Because the CU has determined a mapping relationship between the firstdata flow and the first bearer and a mapping relationship between thesecond data flow and the first bearer, the CU may determine a QoSparameter of the first bearer based on the QoS parameter of the firstdata flow and the QoS parameter of the second data flow.

Specifically, the CU may determine, as the QoS parameter of the firstbearer, a QoS parameter of the first data flow or the second data flowwhose QoS parameter has a stricter requirement.

The 5G QCI is used as an example. As shown in Table 5, a packet delaybudget of the first data flow is 200 ms, a packet delay budget of thesecond data flow is 250 ms, and therefore a packet delay budget of thefirst bearer is 200 ms. Other parameters are in a similar case.

TABLE 5 QoS parameter QoS QoS parameter of the first parameter of the ofthe Parameter type data flow second data flow first bearer GBR ornon-GBR Non-GBR Non-GBR Non GBR type information Priority level 3 4 3Packet delay 200 ms 250 ms 200 ms budget Packet error rate 0.000010.00001 0.00001

Alternatively, the CU may use, as the QoS parameter of the first bearer,a QoS parameter obtained by performing averaging operation processing onthe QoS parameters of the first data flow and the second data flow.Details are shown in Table 6.

TABLE 6 QoS parameter QoS QoS parameter of the first parameter of the ofthe Parameter type data flow second data flow first bearer GBR ornon-GBR GBR GBR GBR type information Priority level 2 4 3 Packet delaybudget 200 ms 300 ms 250 ms Packet error rate 0.00001 0.00001 0.00001GFBR 200 Mbps 300 Mbps 250 bps MFBR 500 Mbps 500 Mbps 500 Mbps

When the CU maps the third data flow to the second bearer, because onlythe third data flow is mapped to the second bearer, the CU may directlydetermine the QoS parameter of the third data flow as a QoS parameter ofthe second bearer. Details are shown in Table 7.

TABLE 7 QoS parameter of QoS parameter of the Parameter type the thirddata flow second bearer GBR or non-GBR type GBR GBR information Prioritylevel 2 2 Packet delay budget 200 ms 200 ms Packet error rate 0.000010.00001 GFBR 200 Mbps 200 bps MFBR 500 Mbps 500 Mbps

140. The CU sends the QoS parameter of the bearer to a distributed unitDU.

Function division for a base station (for example, an eNB in an LTEsystem or a gNB in an NR system) is discussed in an existing standard,to divide the base station into a CU and a DU. A relatively possibleimplementation is division based on functions of protocol stacks. A CUhas functions of layers (including a PDCP layer, an RRC layer, and anSDAP layer) above the PDCP layer, and a DU has functions of layers(including an RLC layer, a MAC layer, and a PHY) below the PDCP layer.After receiving the QoS parameter of the bearer, the DU may schedule thebearer based on the QoS parameter of the bearer. It should be understoodthat the scheduling, by the DU, the bearer may be: controlling, by theDU, data transmission on the bearer.

The scheduling, by the DU, the bearer based on the QoS parameter of thebearer may be specifically:

(1) preferentially scheduling, by the DU, a bearer with a higherpriority based on priority levels of bearers; and

(2) controlling, by the DU, data transmission on the bearer based on apacket delay and a data packet error rate of the bearer, so that thedata transmission on the bearer meets requirements on the packet delayand the data packet error rate.

A principle of scheduling, by the DU, the bearer based on another QoSparameter of the bearer is similar. Details are not described herein oneby one.

In addition, it may be understood that from a perspective of a data flowdirection, the scheduling, by the DU, the bearer may be classified intouplink data scheduling and downlink data scheduling.

Uplink data and downlink data scheduling processes are specifically asfollows:

Downlink Data Scheduling:

The DU schedules downlink data on the bearer based on the QoS parameterof the bearer.

The DU preferentially schedules a bearer with a relatively higherpriority level, and ensures that the requirements on the packet delaybudget and the packet error rate are met for the bearer.Correspondingly, the UE detects downlink scheduling information bydetecting a physical downlink control channel, and receives, on acorresponding physical downlink shared channel based on the downlinkscheduling information, the downlink data sent by the DU.

Uplink Data Scheduling:

The UE requests, from the DU based on configuration information of thebearer, a resource for sending uplink data. For example, the UE sends alogical channel priority of the bearer and an amount of cached data tothe DU. The DU generates an uplink (UL) grant based on the UE-reportedlogical channel priority of the bearer and amount of the cached data andthe QoS parameter corresponding to the bearer, and sends the uplinkgrant to the UE through a physical downlink control channel. The UEsends the uplink data based on the received uplink grant.

In this application, the CU determines the QoS parameter of the bearerand the mapping relationship between the QoS data flow and the bear.This conforms to a CU-DU function division trend. To be specific, boththe QoS parameter of the bearer and the mapping relationship between theQoS data flow and the bear are determined at the SDAP layer of the CU.This can keep consistency between the bearer and the QoS parameter ofthe bearer to the greatest extent, and helps the DU schedule the bearerbased on the QoS parameter of the bearer.

Optionally, for step 140, a specific implementation of the sending, bythe CU, the QoS parameter of the bearer to the DU may include: sending,by the CU, a first message to the DU, where the first message includesthe QoS parameter of the bearer.

The following uses a bearer setup process and a bearer modificationprocess to describe the sending, by the CU, a first message to the DU.

Manner 1: Bearer Setup Process

When the bearer has not been established, the CU may send a bearer setuprequest message to the DU, to establish the bearer.

In this embodiment of this application, the bearer setup request messageis used to carry the QoS parameter of the bearer that is determined bythe CU based on the QoS parameter of the QoS data flow, so as toimplement transferring or indication of the foregoing content from theCU to the DU.

The bearer setup request message may include a configuration parameterof the bearer on the DU. After receiving the first message, the DUconfigures an L1/L2 layer on a DU side based on the configurationparameter of the bearer on the DU.

The bearer setup request message may further include UE-relatedconfiguration information of the bearer. The UE-related configurationinformation of the bearer may be carried in a Radio Resource Controlconnection reconfiguration message generated by the CU.

After receiving the bearer setup request message sent by the CU, the DUmay further send, to the UE, the UE-related configuration information ofthe bearer that is in the bearer setup request message, so that the UEcan configure the bearer based on the UE-related configurationinformation of the bearer, and establish the bearer between the DU andthe UE. The UE-related configuration information of the bearer may bethe radio resource control connection reconfiguration message generatedby the CU.

After the bearer is established, the DU may send a bearer setup responsemessage to the CU, to notify the CU that the bearer between the DU andthe UE has been established. In other words, the method may furtherinclude: receiving, by the CU, a bearer setup response message sent bythe DU.

It can be learned from the foregoing descriptions that the first messagemay be specifically the bearer setup request message, and a responsemessage of the first message may be a bearer setup complete message.

Alternatively, the first message may be specifically a UE context setuprequest message, and a response message of the first message may be a UEcontext setup complete message. An implementation principle and processthereof are similar. Details are not described again.

It should be understood that if the bearer has been established in themanner 1, the bearer may be modified in the following manner 2, and amodified QoS parameter of the bearer is carried in a bearer modificationprocess, so as to implement the transferring or indication of theforegoing content from the CU to the DU.

Manner 2: Bearer Modification Process

If the bearer has been established between the UE and the DU, the CU maysend a bearer modification message to the DU to modify the bearer.Optionally, in an embodiment, the method 100 further includes: sending,by the CU, a second message to the DU, where the second message includesat least one of first information and second information, the firstinformation is a modified QoS parameter of the bearer, and the secondinformation is used to add a QoS data flow to the bearer or remove a QoSdata flow from the bearer. In this case, the second message may bespecifically the bearer modification message.

When the bearer modification message includes the first information, theDU may modify the QoS parameter of the bearer based on the firstinformation. For example, the DU may modify an ARP of the bearer from ahigher priority to a lower priority, or modify an ARP of the bearer froma lower priority to a higher priority.

When the bearer modification message includes the second information,the DU may modify, based on the second information, a data flow includedin the bearer. Specifically, the DU may add a data flow to the bearer,or may remove a data flow from the bearer. For example, the first bearerincludes the first data flow and the second data flow, and the CU sendsa bearer modification message to the DU. After receiving the bearermodification message, the DU adds the third data flow to the data flowsincluded in the first bearer; or after receiving the bearer modificationmessage, the DU removes the second data flow from the first bearer, sothat the first bearer includes only the first data flow.

In this application, the CU can flexibly modify the bearer by sendingthe second message to the DU.

The foregoing embodiment describes the determining, by the CU, the QoSparameter of the bearer and the mapping relationship between the QoSdata flow and the bear, and the scheduling, by the DU, data based on theQoS parameter of the bearer.

It may be understood that in addition to data-flow-level QoS parameters,the QoS parameters further include a slice-level QoS parameter and aUE-level QoS parameter. These non-data-flow-level parameters may beplaced in the first message.

Optionally, in an embodiment, the method 100 further includes:obtaining, by the CU, a non-data-flow-level QoS parameter; sending, bythe CU, a first parameter to the DU; and controlling, by the DU based onthe first parameter, data transmission of any one of a slice, UE, and aPDU session.

In addition to scheduling the bearer based on the QoS parameter of thebearer, the DU may further more precisely control transmission based onthe non-data-flow-level QoS parameter.

It should be understood that the CU may send the first parameter to theDU, so that the DU controls corresponding data transmission based on thefirst parameter; or after obtaining the first parameter, the CU maydirectly control, based on the first parameter, the data transmission ofthe any one of the slice, the UE, and the PDU session.

The first parameter includes any one of or a combination of aslice-level QoS parameter, a UE-level QoS parameter, and a PDUsession-level QoS parameter. When the first parameter includes aparameter at a specific level, the DU may control data transmission atthe level based on the parameter at the level.

The following describes in detail the controlling, by the CU or the DU,corresponding data transmission based on the first parameter by using anexample in which the first parameter includes an uplink PDU sessionaggregate maximum bit rate (AMBR) and a downlink PDU session AMBR.

When the first parameter includes the uplink PDU session AMBR, the CUcontrols an uplink data transmission rate of a PDU session based on theuplink PDU session AMBR, so that the uplink data transmission rate ofthe PDU session meets a requirement on the uplink PDU session AMBR, thatis, a sum of UL data transmission rates of all DRBs in the PDU sessiondoes not exceed the uplink PDU session AMBR.

When the first parameter includes the uplink PDU session AMBR, thesending, by the CU, a first parameter to the DU is: sending the uplinkPDU session AMBR to the DU. After receiving the uplink PDU session AMBR,the DU may control an uplink data transmission rate of a PDU sessionbased on the uplink PDU session AMBR, so that the uplink datatransmission rate of the PDU session meets a requirement on the uplinkPDU session AMBR, that is, a sum of UL data transmission rates of allDRBs in the PDU session does not exceed the uplink PDU session AMBR.

When the first parameter includes the downlink PDU session AMBR, thesending, by the CU, a first parameter to the DU is: sending the downlinkPDU session AMBR to the DU. After receiving the downlink PDU sessionAMBR, the DU may control a downlink data transmission rate of a PDUsession based on the downlink PDU session AMBR, so that the downlinkdata transmission rate of the PDU session meets a requirement on thedownlink PDU session AMBR, that is, a sum of DL data transmission ratesof all DRBs in the PDU session does not exceed the downlink PDU sessionAMBR.

When the first parameter includes both the uplink PDU session AMBR andthe downlink PDU session AMBR, the CU sends both the uplink PDU sessionAMBR and the downlink PDU session AMBR to the DU, so that the DU cancontrol an uplink data transmission rate and a downlink datatransmission rate of a PDU session based on the uplink PDU session AMBRand the downlink PDU session AMBR, the uplink data transmission rate ofthe PDU session meets a requirement on the uplink PDU session AMBR, andthe downlink data transmission rate of the PDU session meets arequirement on the downlink PDU session AMBR, that is, a sum of UL datatransmission rates of all DRBs in the PDU session does not exceed theuplink PDU session AMBR, and a sum of DL data transmission rates of allDRBs in the PDU session does not exceed the downlink PDU session AMBR.

A process of controlling, by the CU or the DU, corresponding datatransmission based on a slice-level QoS parameter or a UE-level QoSparameter is similar to the foregoing control process. Details are notdescribed herein again.

FIG. 2 is a flowchart of a communication method 200 according to anembodiment of this application. Specific steps of the communicationmethod 200 are as follows.

210. A CU obtains a QoS parameter of a QoS data flow.

220. The CU determines a mapping information between the QoS data flowand a bearer based on the QoS parameter of the QoS data flow.

It should be understood that step 210 and step 220 are the same as step110 and step 120, and the foregoing descriptions of step 110 and step120 are also applicable to step 210 and step 220. For brevity, repeateddescriptions are properly omitted.

230. The CU sends, to a DU, the QoS parameter of the QoS data flow andthe mapping information between the QoS data flow and the bearer.

The mapping information may be used to indicate a mapping relationshipbetween the QoS data flow and the bearer. For example, a specific dataflow is mapped to a specific bearer. A specific form of the mappinginformation may be shown in Table 8. Table 8 shows mapping informationof a specific bearer. The mapping information of the bearer includes anidentifier of the bearer and a QoS data flow included in the bearer.

TABLE 8 Bearer > Identifier of the bearer > List of an identifier of aQoS data flow included in the bearer

Further, the mapping information of the bearer in Table 8 may furtherinclude a QoS parameter of the QoS data flow included in the bearer, asshown in Table 9.

TABLE 9 Bearer > Identifier of the bearer > List of an identifier of aQoS data flow included in the bearer >> QoS parameter of the QoS dataflow included in the bearer

In this application, the DU can flexibly schedule the bearer based onthe QoS parameter of the QoS data flow and the mapping informationbetween the QoS data flow and the bearer. For example, a medium accesscontrol (MAC) layer of the DU can flexibly schedule the bearer based oninformation such as load, the QoS parameter of the QoS data flow, andthe mapping information between the QoS data flow and the bearer.

Specifically, when the bearer includes a relatively small quantity ofQoS data flows or the QoS data flows have relatively similar QoSparameters, the CU may directly schedule the bearer based on the QoSparameters of the QoS data flows included in the bearer. However, whenthe bearer includes a relatively large quantity of QoS data flows or theQoS data flows have greatly different QoS parameters, the CU maygenerate a QoS parameter of the bearer based on the QoS parameters ofthe QoS data flows, and then schedule the bearer based on the QoSparameter of the bearer.

Optionally, the method 100 and the method 200 are also applicable to aCU/DU handover scenario.

With reference to FIG. 3 and FIG. 4, the following describes in detailtwo scenarios: inter-base-station handover and intra-base-stationhandover.

Scenario 1: Inter-Base-Station Handover

As shown in FIG. 3, when UE needs to be handed over from a current basestation to a target base station, for the method 100, the current basestation may send, to the target base station, a mapping relationshipbetween a QoS data flow and a bearer and a CU-determined QoS parameterof the bearer, so that a target DU can schedule the bearer based on theinformation.

Specifically, the current base station includes a current CU and acurrent DU, and the target base station includes a target CU and thetarget DU. The current CU may send, to the target CU through an Xninterface, the mapping relationship between the QoS data flow and thebearer and the CU-determined QoS parameter of the bearer. Then, thetarget CU sends the mapping relationship and the QoS parameter of thebearer to the target DU through an F1 interface, so that the target DUcan schedule the bearer based on the information. For example, thecurrent CU sends a handover request message to the target CU, where thehandover request message includes the mapping relationship between theQoS data flow and the bearer and the CU-determined QoS parameter of thebearer.

As shown in FIG. 3, when UE needs to be handed over from a current basestation to a target base station, for the method 200, the current basestation may send, to the target base station, a mapping relationshipbetween a QoS data flow and a bearer and a QoS parameter of the QoS dataflow, so that a target DU can schedule the bearer based on theinformation.

Specifically, the current base station includes a current CU and acurrent DU, and the target base station includes a target CU and thetarget DU. The current CU may send, to the target CU through an Xninterface, the mapping relationship between the QoS data flow and thebearer and the QoS parameter of the QoS data flow. Then, the target CUsends the mapping relationship and the QoS parameter of the QoS dataflow to the target DU through an F1 interface, so that the target DU canschedule the bearer based on the information. For example, the currentCU sends a handover request message to the target CU, where the handoverrequest message includes the mapping relationship between the QoS dataflow and the bearer and the QoS parameter of the QoS data flow.

Scenario 2: Intra-Base-Station Handover Between DUs

As shown in FIG. 4, when UE needs to be handed over from a current DU toa target DU, for the method 100, a CU may send, to the target DU throughan F1 interface, a mapping relationship between a QoS data flow and abearer and a CU-determined QoS parameter of the bearer, so that thetarget DU can schedule the bearer based on the information. For example,the CU sends a UE context setup request message to the target DU, wherethe UE context setup request message includes the mapping relationshipbetween the QoS data flow and the bearer and the CU-determined QoSparameter of the bearer.

As shown in FIG. 4, when UE needs to be handed over from a current DU toa target DU, for the method 200, a CU may send, to the target DU throughan F1 interface, a mapping relationship between a QoS data flow and abearer and a QoS parameter of the QoS data flow, so that the target DUcan schedule the bearer based on the information. For example, the CUsends a UE context setup request message to a target DU, where the UEcontext setup request message includes the mapping relationship betweenthe QoS data flow and the bearer and the QoS parameter of the QoS dataflow.

In addition, the method 100 and the method 200 may also be applicable toa dual connectivity (DC) scenario.

As shown in FIG. 5, when UE retains connections to both a primary basestation and a secondary base station, the primary base station sends, tothe secondary base station, a mapping relationship between a QoS dataflow and a bearer and a CU-determined QoS parameter of the bearer, sothat the secondary base station can schedule the bearer based on theinformation. For example, the primary base station sends a secondarybase station add message to the secondary base station, where thesecondary base station add message includes the mapping relationshipbetween the QoS data flow and the bearer and the QoS parameter of thebearer that is determined by the primary base station.

Specifically, a CU of the primary base station may send, to a CU of thesecondary base station through an Xn interface, the mapping relationshipbetween the QoS data flow and the bearer and the QoS parameter of thebearer that is determined by the CU of the primary base station. Then,the CU of the secondary base station sends the information to a DU ofthe secondary base station through an F1 interface, so that the DU ofthe secondary base station can schedule the bearer based on theinformation.

As shown in FIG. 5, when UE retains connections to both a primary basestation and a secondary base station, the primary base station may send,to the secondary base station, a mapping relationship between a QoS dataflow and a bearer and a QoS parameter of the QoS data flow, so that thesecondary base station can schedule the bearer based on the information.For example, the primary base station sends a secondary base station addmessage to the secondary base station, where the secondary base stationadd message includes the mapping relationship between the QoS data flowand the bearer and the QoS parameter of the QoS data flow.

Specifically, a CU of the primary base station may send, to a CU of thesecondary base station through an Xn interface, the mapping relationshipbetween the QoS data flow and the bearer and the QoS parameter of theQoS data flow. Then, the CU of the secondary base station sends theinformation to a DU of the secondary base station through an F1interface, so that the DU of the secondary base station can schedule thebearer based on the information.

The foregoing describes the communication methods in the embodiments ofthis application from a perspective of a CU with reference to FIG. 1 andFIG. 2. The following describes communication methods in the embodimentsof this application from a perspective of a DU with reference to FIG. 6and FIG. 7. It should be understood that the communication methods inFIG. 6 and FIG. 7 are corresponding to the communication methods in FIG.1 and FIG. 2 respectively. For brevity, repeated descriptions areproperly omitted.

FIG. 6 is a flowchart of a communication method 600 according to anembodiment of this application. Specific steps of the communicationmethod 600 are as follows:

610. A distributed unit DU receives a QoS parameter of a bearer that issent by a central unit CU, where the bearer is a bearer that isdetermined by the CU based on a QoS parameter of a QoS data flow andthat has a mapping relationship with the QoS data flow, and the QoSparameter of the bearer is determined by the CU based on the QoSparameter of the QoS data flow.

620. The DU schedules the bearer based on the QoS parameter of thebearer.

In this application, the QoS parameter of the bearer, based on which theDU schedules the bearer, is determined when the CU determines themapping relationship between the QoS data flow and the bear. This cankeep consistency between the bearer and the QoS parameter of the bearer,and can improve an effect of scheduling the bearer by the DU.

FIG. 7 is a flowchart of a communication method 700 according to anembodiment of this application. Specific steps of the communicationmethod 700 are as follows:

710. A distributed unit DU receives a QoS parameter of a QoS data flowand mapping information between the QoS data flow and the bearer, wherethe QoS parameter of the QoS data flow and the mapping information aresent by a central unit CU.

720. The DU schedules the bearer based on the QoS parameter of the QoSdata flow and the mapping information between the QoS data flow and thebearer.

In this application, the DU can schedule the bearer based on the QoSparameter of the QoS data flow and the mapping information between theQoS data flow and the bearer. The DU may directly schedule the bearerbased on a QoS-data-flow-level QoS parameter; or may convert the QoSparameter of the QoS data flow into a bearer-level QoS parameter, andthen schedule the bearer. Compared with a manner of scheduling a bearerbased only on a QoS parameter of the bearer, this improves flexibilityfor scheduling a bearer.

Optionally, in an embodiment, in the method 600 and the method 700, themapping information is determined by the CU based on a result ofcomparison on the QoS parameter of the QoS data flow.

Optionally, in an embodiment, in the method 600 and the method 700,there is a mapping relationship between the bearer and a plurality ofdata flows in the QoS data flow, and the QoS parameter of the bearer isselected by the CU from QoS parameters of the plurality of data flows,or the QoS parameter of the bearer is obtained by the CU throughcalculation based on QoS parameters of the plurality of data flows.

Optionally, in an embodiment, the method 600 and the method 700 furtherinclude: receiving, by the DU, a first message sent by the CU, where thefirst message includes the QoS parameter of the bearer and/or themapping information between the QoS data flow and the bearer; andestablishing, by the DU, the bearer between the DU and user equipment UEbased on the first message.

Optionally, in an embodiment, the method 600 and the method 700 furtherinclude: receiving, by the DU, a first message sent by the CU, where thefirst message includes the QoS parameter of the QoS data flow and/or themapping information between the QoS data flow and the bearer; andestablishing, by the DU, the bearer between the DU and user equipment UEbased on the first message.

Optionally, in an embodiment, the method 600 and the method 700 furtherinclude: receiving, by the DU, a bearer modification message sent by theCU, where the bearer modification message includes at least one of firstinformation and second information, the first information is a modifiedQoS parameter of the bearer, and the second information is used to add aQoS data flow to the bearer or remove a QoS data flow from the bearer.

Optionally, in an embodiment, in the method 600 and the method 700, themapping information between the QoS data flow and the bearer isdetermined by the CU at a Service Data Adaptation Protocol SDAP layer.

Optionally, in an embodiment, the method 600 and the method 700 furtherinclude: receiving, by the DU, a non-QoS-data-flow-level QoS parametersent by the CU, where the non-QoS-data-flow-level QoS parameter includesany one of a slice-level QoS parameter, a UE-level QoS parameter, and apacket data unit PDU session-level QoS parameter; and controlling, bythe DU based on the non-QoS-data-flow-level QoS parameter, datatransmission of any one of a slice, a UE, and a PDU session.

The foregoing describes the communication methods in the embodiments ofthis application from the perspective of the DU with reference to FIG. 6and FIG. 7. The following describes a communication method in theembodiments of this application from a perspective of UE with referenceto FIG. 8. It should be understood that the communication method in FIG.8 is corresponding to the communication methods in FIG. 6 and FIG. 7.For brevity, repeated descriptions are properly omitted.

FIG. 8 is a flowchart of a communication method 800 according to anembodiment of this application. Specific steps of the communicationmethod 800 are as follows:

810. UE obtains mapping information between a QoS data flow and abearer, where the mapping information is determined by a CU based on aQoS parameter of the QoS data flow.

820. The UE sends uplink data to a DU based on a mapping relationshipbetween the QoS data flow and the bearer.

In this application, the mapping information between the QoS data flowand the bearer, based on which the UE transmits the uplink data, isdetermined by the CU based on the QoS parameter of the QoS data flow.This conforms to a CU-DU function division trend, and can ensure aneffect of transmitting the uplink data by the UE.

Optionally, in an embodiment, the obtaining, by UE, mapping informationbetween a QoS data flow and a bearer includes: receiving, by the UE, aradio resource control connection reconfiguration message sent by theDU; and obtaining, by the UE, the mapping relationship between the QoSdata flow and the bearer from the radio resource control connectionreconfiguration message.

Optionally, in an embodiment, the method 800 further includes:receiving, by the UE, a bearer modification message sent by the DU,where the bearer modification message includes at least one of firstinformation and second information, the first information is a modifiedQoS parameter of the bearer, and the second information is used to add aQoS data flow to the bearer or remove a QoS data flow from the bearer;determining, by the UE, the QoS parameter of the bearer based on thebearer modification message; and/or adding, by the UE, a QoS data flowto the bearer or removing a QoS data flow from the bearer based on thebearer modification message.

The following describes in detail communication methods in theembodiments of this application with reference to FIG. 9 to FIG. 12. Thecommunication methods in FIG. 9 to FIG. 12 may be implemented by adevice such as the CU, the DU, or the UE in the foregoing descriptions.

FIG. 9 is a flowchart of a communication method according to anembodiment of this application. The method in FIG. 9 includes thefollowing steps.

901. A CU sends a bearer setup request to a DU.

The bearer setup request may include the following information: a listof to-be-setup DRB, where the list includes a DRB ID and a QoS parameterof the to-be-setup DRB, a mapping relationship between a QoS data flowand the to-be-setup DRB, and a tunnel endpoint identifier (TEID) of theCU.

After obtaining the bearer setup request, the CU may first determine theDRB that needs to be established, and then maps the QoS data flow to thecorresponding DRB based on the tunnel endpoint identifier of the CU andthe mapping relationship between the QoS data flow and the DRB.

Specifically, the bearer setup request may specifically includeinformation shown in Table 10.

TABLE 10 Bearer setup list > Identifier of a PDU session to which abearer belongs >> QoS parameter of the PDU session (a PDU sessionAMBR) >>> Identifier of a DRB >>> List of a QoS flow included in theDRB >>>> QoS parameter of the QoS flow >>>> QoS parameter of theDRB >>>> Uplink transmission link address of the DRB UE-relatedconfiguration information of the DRB Configuration parameter of the DRBon the DU

902. The DU sends a bearer setup response to the CU.

The bearer setup response may include a list of DRB which isestablished, and the list includes a DRB ID and a DRB TEID of the DRBthat has been successfully established. In addition, the bearer setupresponse may further include a list of DRB which failed to beestablished, and the list includes a DRB ID of the DRB subject to thebearer setup failure and a cause of the DRB setup failure.

The CU sends the bearer setup request to the DU, so that the DU canestablish a DRB between UE and the DU, and after the DRB is established,the DU feeds back to the CU that the DRB has been established.

FIG. 10A and FIG. 10B are a flowchart of a communication methodaccording to an embodiment of this application. The method in FIG. 10Aand FIG. 10B includes the following steps.

1001. A CU receives a QoS data flow sent by an access and mobilitymanagement function (AMF) unit.

Specifically, the CU obtains the QoS data flow through a PDU session.The QoS data flows include three data flows. The three data flows are aflow 1, a flow 2, and a flow 3. The three data flows include QoS dataflow IDs (a QFI1, a QFI2, and a QFI3) and corresponding data.

1002. The CU maps a flow 1 and a flow 2 to a bearer 1, and maps a flow 3to a bearer 2.

Optionally, the CU may map, to a same bearer, QoS data flows that havesimilar QoS parameters. Therefore, when a QoS parameter of the flow 1and a QoS parameter of the flow 2 are relatively similar, and a QoSparameter of the flow 3 is greatly different from the QoS parameter ofthe flow 1 and the QoS parameter of the flow 2, the flow 1 and the flow2 may be mapped to a same bearer, and the flow 3 is mapped to anotherbearer. In other words, one bearer may include one QoS data flow, or mayinclude a plurality of QoS data flows. In addition, mapping, by the CU,the QoS data flows to the bearers may be specifically implemented by anSDAP layer of the CU.

1003. The CU generates a QoS parameter of the bearer 1 based on QoSparameters of the flow 1 and the flow 2, and generates a QoS parameterof the bearer 2 based on a QoS parameter of the flow 3.

Before generating the QoS parameters of the bearers based on the QoSdata flows, the CU may first determine the QoS parameters of the QoSdata flows. Specifically, the CU may determine the QoS parameters of theQoS data flows based on the QoS data flow IDs and a correspondencebetween QoS data flow IDs and QoS parameters. The correspondence betweenthe QoS data flow IDs and the QoS parameters may be preset on the CU, ormay be carried in a PDU session setup request initiated by a corenetwork to a DU, or may be stipulated in a communication standard.

In addition, when determining QoS parameters of a plurality of bearersbased on QoS parameters of a plurality of QoS data flows, the CU mayselect, from the QoS parameters of the plurality of QoS data flows basedon parameter values of the QoS parameters, QoS parameters with strictestparameter values as the QoS parameters of the bearers. Specifically, itis assumed that the flow 1 and the flow 2 are mapped to the bearer 1,and the flow 3 is mapped to the bearer 2. When the CU generates the QoSparameter of the bearer 1 based on the QoS parameters of the flow 1 andthe flow 2, the CU may select, from the QoS parameters of the flow 1 andthe flow 2, a QoS parameter with a strictest parameter value as the QoSparameter of the bearer 1; or may use, as the QoS parameter of thebearer 1, a QoS parameter obtained by performing averaging on the QoSparameters of the flow 1 and the flow 2. When the CU generates the QoSparameter of the bearer 2 based on the QoS parameter of the flow 3, theCU may directly use the QoS parameter of the flow 3 as the QoS parameterof the bearer 2.

1004. The CU sends the QoS parameters of the bearers to a DU.

Specifically, the QoS parameters of the bearers may be carried in abearer setup request message or a UE context setup request message sentby the CU.

If no bearer has been established between the DU and UE, the CU may sendthe bearer setup request message to the DU, so that the DU establishes abearer between the DU and the UE.

In a case of initial bearer setup, the CU sends the UE context setuprequest message to the DU.

The bearer setup request message or the UE context setup request messagemay include the QoS parameters of the bearers that are generated basedon the QoS parameters of the QoS data flows, configuration parameters ofthe bearers on the DU, UE-related configuration information of thebearers, uplink transmission link addresses of the bearers, and thelike. The uplink transmission link addresses of the bearers include GPRSTunneling Protocol (GTP) tunnel endpoint identifiers.

A specific format of the bearer setup request message or the UE contextsetup request message may be shown in Table 11.

TABLE 11 Bearer setup list > Identifier of a PDU session to which thebearers belong >> QoS parameter of the PDU session (a PDU sessionAMBR) >>> Identifiers of the bearers >>>> QoS parameters of thebearers >>>> Uplink transmission link addresses of the bearersUE-related configuration information of the bearers Configurationparameters of the bearers on the DU

It should be understood that the bearer setup request message or the UEcontext setup request message may further include a UE-level parameter(for example, an AMBR of the UE) and a slice-level parameter (forexample, an AMBR of a slice), in addition to the parameters shown inTable 11.

After receiving the bearer setup request message sent by the CU, the DUconfigures an L1 layer and/or an L2 layer on a DU side based on theconfiguration parameters of the bearers on the DU included in the bearersetup request message.

1005. The DU sends UE-related configuration information of the bearersto UE.

Specifically, the UE-related configuration information of the bearersmay be a Radio Resource Control connection reconfiguration message.

The Radio Resource Control connection reconfiguration message includesUE-related configuration information of the bearers.

1006. The UE configures the bearer 1 and the bearer 2 based on theUE-related configuration information of the bearers.

The UE configures the bearers based on the UE-related configurationinformation of the bearers that is in the Radio Resource Controlconnection reconfiguration message.

1007. The UE sends a radio resource control (RRC) connectionreconfiguration complete message to the DU.

After configuring the bearers, the UE feeds back the radio resourcecontrol connection reconfiguration complete message to the DU.

1008. The DU sends a bearer setup complete message to the CU.

The DU may send the bearer setup complete message to the CU, or may senda UE context setup complete message to the CU.

After receiving the radio resource control connection reconfigurationcomplete message fed back by the CU, the DU feeds back the bearer setupcomplete message to the CU. The bearer setup complete message includesdownlink transmission link addresses (including GTP tunnel endpointidentifiers) of the bearers and the like.

It should be understood that step 1004 to step 1008 are optional. Whenthe bearers have not been established, step 1004 to step 1008 may beperformed to establish the bearers. If the bearers have beenestablished, the bearers may be directly scheduled after step 1003 isperformed.

Optionally, if the bearers have been established, after performing step1003, the CU may send a bearer modification message to the DU to modifythe bearers. For example, the CU may modify some QoS parameters of thebearers, or add a QoS data flow to the bearers or remove a QoS data flowfrom the bearers. After the bearers are modified, modified bearers maybe scheduled.

It should be understood that, on the foregoing basis, the DU mayalternatively schedule the bearers based on a UE-level parameter, a PDUsession-level parameter, and the QoS parameters of the bearers.

Specifically, the scheduling, by the DU, the bearers may be classifiedinto uplink data scheduling for the bearers and downlink data schedulingfor the bearers.

Downlink data scheduling for the bearers:

The DU receives downlink data sent by a core network through a sessiontunnel. Then, an SDAP layer of the DU maps the QoS data flows to thebearers by identifying the QFIs, and transfers the data to a PDCP layer.The PDCP layer performs encryption, integrity protection, and the like,and then sends the data to the corresponding bearers between the DU andthe UE.

Uplink data scheduling for the bearers:

After receiving uplink data on the bearers, the DU sends data packets tothe CU based on the uplink transmission link addresses (including theGTP tunnel endpoint identifiers) of the bearers. After receiving thedata packets on the bearers, the CU sends the data packets to the corenetwork through PDU session tunnels corresponding to the bearers.

In addition, when generating the QoS parameters of the bearers in step1003, the CU may also generate uplink scheduling information of thebearers. The uplink scheduling information may include a logicalchannel, a logical channel scheduling priority, and the like. The CUadds the uplink scheduling information to the configuration parametersof the bearers on the DU and UE-related configuration parameters of thebearers. After obtaining the uplink scheduling information, the DU andthe UE may transmit the uplink data based on the uplink schedulinginformation, and send an uplink mapping relationship between the QoSdata flows and the bearers to the UE. Usually, uplink data and downlinkdata of one QoS data flow are mapped to a same bearer.

For example, the UE maps the QoS data flows to the corresponding bearersbased on the uplink mapping relationship between the QoS data flows andthe bearers, and adds the DFIs. The DU allocates an uplink (UL) grant tothe UE based on the uplink scheduling information. After receiving theuplink grant, the UE preferentially allows a bearer with a higherlogical channel priority to use the uplink grant, and preferentiallysends data on a bearer with a higher priority. In addition, afterreceiving the uplink data, the DU sends the uplink data to the CUthrough an uplink GTP tunnel. The CU identifies the bearer based on aTEID of the uplink GTP tunnel. After performing data decryption orintegrity check on the bearer, a PDCP layer of the CU transfers the datato an SDAP layer. The SDAP layer identifies a data flow based on a DFIin a data packet header, identifies session information based on theDFI, and sends the data to the core network through a tunnelcorresponding to the session.

The DU may further schedule the bearers based on parameters such as a5QI, an ARP, a GBR, and a maximum bit rate (MBR). For example, when the5QI includes priority levels of different bearers, the DU maypreferentially schedule a bearer with a higher priority. When the 5QIincludes a packet delay budget and a data packet error rate, the DU maycontrol data transmission of the bearers, so that the data transmissionof the bearers meets requirements on the packet delay and the datapacket error rate.

FIG. 11A and FIG. 11B are a flowchart of a communication methodaccording to an embodiment of this application. The method in FIG. 11Aand FIG. 11B includes the following steps.

1101. A CU receives a QoS data flow sent by a core network.

1102. The CU maps a flow 1 and a flow 2 to a bearer 1, and maps a flow 3to a bearer 2.

1103. The CU sends a QoS parameter of the QoS data flow to a DU.

Specifically, QoS parameters of the bearers may be carried in a bearersetup request message or a UE context setup request message sent by theCU.

A format of the bearer setup request message or the UE context setuprequest message may be specifically a form shown in Table 12.

TABLE 12 Bearer setup list > Identifier of a PDU session to which thebearers belong >> QoS parameter of the PDU session (a PDU SessionAMBR) >>> Identifiers of the bearers >>> List of QoS flows included inthe bearers >>>> QoS parameters of the QoS flows >>>> Uplinktransmission link addresses of the bearers UE-related configurationinformation of the bearers Configuration parameters of the bearers onthe DU

1104. The DU generates a QoS parameter of the bearer 1 based on QoSparameters of the flow 1 and the flow 2, and generates a QoS parameterof the bearer 2 based on a QoS parameter of the flow 3.

In the method in FIG. 10A and FIG. 10B, the CU generates the QoSparameters of the bearers based on the QoS data flows; however, in themethod in FIG. 11A and FIG. 11B, the DU generates the QoS parameters ofthe bearers based on the QoS data flows. In addition, before generatingthe QoS parameters of the bearers based on the QoS data flows, the DUmay first obtain mapping information between the QoS data flows and thebearers from the CU. Specifically, before step 1103, the DU obtains themapping information from the CU (or the CU may directly notify the DU ofthe mapping information), that is, the DU learns, from the CU, that theflow 1 and the flow 2 are mapped to the bearer 1 and the flow 3 ismapped to the bearer 2.

1105. The DU sends a Radio Resource Control connection reconfigurationmessage to UE.

1106. The UE configures the bearer 1 and the bearer 2 based on the RadioResource Control connection reconfiguration message.

1107. The UE sends a Radio Resource Control connection reconfigurationcomplete message to the DU.

1108. The DU sends a bearer setup complete message to the CU.

Similar to the method in FIG. 10A and FIG. 10B, step 1104 to step 1108are optional. When the bearers have not been established, step 1104 tostep 1108 may be performed to establish the bearers. If the bearers havebeen established, the bearers may be directly scheduled after step 1103is performed.

It should be understood that, on the foregoing basis, the DU mayalternatively schedule the bearers based on a UE-level parameter, a PDUsession-level parameter, and the QoS parameters of the bearers.

For a specific process of scheduling the bearers by the DU, refer to thescheduling the bearers by the DU in the method shown in FIG. 10A andFIG. 10B. Details are not described herein again.

In this application, the DU may schedule the bearers based onbearer-level QoS parameters, or may perform corresponding schedulingbased on parameters at other levels (such as a slice-level parameter,the UE-level parameter, and the PDU session-level parameter). Withreference to FIG. 12 and FIG. 13, the following uses a PDU session AMBRas an example to describe in detail a PDU session scheduling processwhen data bearers include a bearer 1 and a bearer 2.

FIG. 12 is a flowchart of a communication method according to anembodiment of this application. The method in FIG. 12 includes thefollowing steps.

1201. A CU manages radio resources of a bearer 1 and a bearer 2 based ona downlink PDU session AMBR.

Specifically, the CU controls a downlink data transmission rate of a PDUsession based on the downlink PDU session AMBR, so that a sum ofdownlink data transmission rates of the bearer 1 and the bearer 2 in thePDU session does not exceed the downlink PDU session AMBR.

1202. The CU sends an uplink PDU session AMBR to a DU.

1203. The DU manages the radio resources of the bearer 1 and the bearer2 based on the uplink PDU session AMBR.

Specifically, the DU controls an uplink data transmission rate of thePDU session based on the uplink PDU session AMBR, so that a sum ofuplink data transmission rates of the bearer 1 and the bearer 2 in thePDU session does not exceed the uplink PDU session AMBR.

In the communication method shown in FIG. 12, the CU controls the uplinkdata transmission rate of the PDU session, and the DU controls thedownlink data transmission rate of the PDU session. Optionally, the CUmay alternatively send both the uplink PDU session AMBR and the downlinkPDU session AMBR to the DU, so that the DU controls uplink and downlinkdata transmission of the PDU session.

FIG. 13 is a flowchart of a communication method according to anembodiment of this application. The method in FIG. 13 includes thefollowing steps:

1301. A CU sends an uplink PDU session AMBR and a downlink PDU sessionAMBR to a DU.

1302. The DU manages radio resources of a bearer 1 and a bearer 2 basedon the uplink PDU session AMBR and the downlink PDU session AMBR.

Specifically, the DU controls an uplink data transmission rate of a PDUsession based on the uplink PDU session AMBR, and controls a downlinkdata transmission rate of the PDU session based on the downlink PDUsession AMBR, so that a sum of uplink data transmission rates of thebearer 1 and the bearer 2 in the PDU session does not exceed the uplinkPDU session AMBR, and a sum of downlink data transmission rates of thebearer 1 and the bearer 2 does not exceed the downlink PDU session AMBR.

The foregoing describes in detail the communication methods in theembodiments of this application with reference to FIG. 1 to FIG. 13. Thefollowing describes a base station, a terminal device, and acommunications apparatus in the embodiments of this application withreference to FIG. 14 to FIG. 19. It should be understood that the basestation, the terminal device, and the communications apparatus in FIG.14 to FIG. 19 can implement corresponding steps in the communicationmethods in FIG. 1 to FIG. 13. For brevity, repeated descriptions areproperly omitted in the following.

FIG. 14 is a schematic block diagram of a base station 1400 according toan embodiment of this application. The base station 1400 includes:

an obtaining module 1410, configured to obtain a quality of service QoSparameter of a QoS data flow;

a processing module 1420, configured to determine mapping informationbetween the QoS data flow and a bearer based on the QoS parameter of theQoS data flow, where

the processing module 1420 is further configured to determine a QoSparameter of the bearer based on the QoS parameter of the QoS data flow;and

a sending module 1430, configured to send the QoS parameter of thebearer to a distributed unit DU.

Optionally, in an embodiment, the processing module 1420 is specificallyconfigured to determine the mapping information between the QoS dataflow and the bearer based on a result of comparison on the QoS parameterof the QoS data flow.

Optionally, in an embodiment, there is a mapping relationship betweenthe bearer and a plurality of data flows in the QoS data flow, and theprocessing module 1420 is specifically configured to: select the QoSparameter of the bearer from QoS parameters of the plurality of dataflows; or calculate the QoS parameter of the bearer based on QoSparameters of the plurality of data flows.

Optionally, in an embodiment, the sending module 1430 is furtherconfigured to send a first message to the DU, where the first messageincludes the QoS parameter of the bearer and/or the mapping informationbetween the QoS data flow and the bearer, and the first message is usedto request the DU to establish the bearer between the DU and userequipment UE.

Optionally, in an embodiment, the sending module 1430 is furtherconfigured to send a bearer modification message to the DU, where thebearer modification message includes at least one of first informationand second information, the first information is a modified QoSparameter of the bearer, and the second information is used to add a QoSdata flow to the bearer or remove a QoS data flow from the bearer.

Optionally, in an embodiment, the processing module 1420 is specificallyconfigured to determine, at a Service Data Adaptation Protocol SDAPlayer, the mapping information between the QoS data flow and the bearer.

Optionally, in an embodiment, the obtaining module 1410 is furtherconfigured to obtain a non-QoS-data-flow-level QoS parameter, where thenon-QoS-data-flow-level QoS parameter includes any one of a slice-levelQoS parameter, a UE-level QoS parameter, and a packet data unit PDUsession-level QoS parameter; and the sending module 1430 is furtherconfigured to send the first parameter to the DU.

Optionally, in an embodiment, the obtaining module 1410 is furtherconfigured to obtain a non-QoS-data-flow-level QoS parameter, where thenon-QoS-data-flow-level QoS parameter includes any one of a slice-levelQoS parameter, a UE-level QoS parameter, and a packet data unit PDUsession-level QoS parameter; and the processing module 1420 isspecifically configured to control, based on the non-QoS-data-flow-levelQoS parameter, data transmission of any one of a slice, a UE, and a PDUsession.

FIG. 15 is a schematic block diagram of a base station 1500 according toan embodiment of this application. The base station 1500 includes:

an obtaining module 1510, configured to obtain a quality of service QoSparameter of a QoS data flow;

a processing module 1520, configured to determine mapping informationbetween the QoS data flow and a bearer based on the QoS parameter of theQoS data flow; and

a sending module 1530, configured to send, to a distributed unit DU, theQoS parameter of the QoS data flow and the mapping information betweenthe QoS data flow and the bearer.

Optionally, in an embodiment, the processing module 1520 is specificallyconfigured to determine the mapping information between the QoS dataflow and the bearer based on a result of comparison on the QoS parameterof the QoS data flow.

Optionally, in an embodiment, the sending module 1530 is furtherconfigured to send a first message to the DU, where the first messageincludes the QoS parameter of the QoS data flow and/or the mappinginformation between the QoS data flow and the bearer, and the firstmessage is used to request the DU to establish the bearer between the DUand user equipment UE.

Optionally, in an embodiment, the sending module 1530 is furtherconfigured to send a bearer modification message to the DU, where thebearer modification message includes at least one of first informationand second information, the first information is a modified QoSparameter of the bearer, and the second information is used to add a QoSdata flow to the bearer or remove a QoS data flow from the bearer.

Optionally, in an embodiment, the processing module 1520 is specificallyconfigured to determine, at a Service Data Adaptation Protocol SDAPlayer, the mapping information between the QoS data flow and the bearer.

Optionally, in an embodiment, the obtaining module 1510 is furtherconfigured to obtain a non-QoS-data-flow-level QoS parameter, where thenon-QoS-data-flow-level QoS parameter includes any one of a slice-levelQoS parameter, a UE-level QoS parameter, and a packet data unit PDUsession-level QoS parameter.

Optionally, in an embodiment, the obtaining module 1510 is furtherconfigured to obtain a non-QoS-data-flow-level QoS parameter, where thenon-QoS-data-flow-level QoS parameter includes any one of a slice-levelQoS parameter, a UE-level QoS parameter, and a packet data unit PDUsession-level QoS parameter.

Optionally, in an embodiment, the processing module 1520 is specificallyconfigured to control, based on the non-QoS-data-flow-level QoSparameter, data transmission of any one of a slice, a UE, and a PDUsession.

FIG. 16 is a schematic block diagram of a base station 1600 according toan embodiment of this application. The base station 1600 includes:

a receiving module 1610, configured to receive a QoS parameter of abearer that is sent by a central unit CU, where the bearer is a bearerthat is determined by the CU based on a QoS parameter of a QoS data flowand that has a mapping relationship with the QoS data flow, and the QoSparameter of the bearer is determined by the CU based on the QoSparameter of the QoS data flow; and

a processing module 1620, configured to schedule the bearer based on theQoS parameter of the bearer.

Optionally, in an embodiment, mapping information is determined by theCU based on a result of comparison on the QoS parameter of the QoS dataflow.

Optionally, in an embodiment, there is a mapping relationship betweenthe bearer and a plurality of data flows in the QoS data flow, and theQoS parameter of the bearer is selected by the CU from QoS parameters ofthe plurality of data flows, or the QoS parameter of the bearer isobtained by the CU through calculation based on QoS parameters of theplurality of data flows.

Optionally, in an embodiment, the receiving module 1610 is furtherconfigured to receive a first message sent by the CU, where the firstmessage includes the QoS parameter of the bearer and/or the mappinginformation between the QoS data flow and the bearer; and

the processing module 1620 is specifically configured to establish thebearer between a DU and user equipment UE based on the first message.

Optionally, in an embodiment, the receiving module 1610 is furtherconfigured to receive a bearer modification message sent by the CU,where the bearer modification message includes at least one of firstinformation and second information, the first information is a modifiedQoS parameter of the bearer, and the second information is used to add aQoS data flow to the bearer or remove a QoS data flow from the bearer.

Optionally, in an embodiment, the mapping information between the QoSdata flow and the bearer is determined by the CU at a Service DataAdaptation Protocol SDAP layer.

Optionally, in an embodiment, the receiving module 1610 is furtherconfigured to receive a non-QoS-data-flow-level QoS parameter sent bythe CU, where the non-QoS-data-flow-level QoS parameter includes any oneof a slice-level QoS parameter, a UE-level QoS parameter, and a packetdata unit PDU session-level QoS parameter; and the processing module1620 is specifically configured to control, based on thenon-QoS-data-flow-level QoS parameter, data transmission of any one of aslice, a UE, and a PDU session.

FIG. 17 is a schematic block diagram of a base station 1700 according toan embodiment of this application. The base station 1700 includes:

a receiving module 1710, configured to receive a QoS parameter of a QoSdata flow and mapping information between the QoS data flow and thebearer, where the QoS parameter of the QoS data flow and the mappinginformation are sent by a central unit CU; and

a processing module 1720, configured to schedule the bearer based on theQoS parameter of the QoS data flow and the mapping information betweenthe QoS data flow and the bearer.

Optionally, in an embodiment, the mapping information is determined bythe CU based on a result of comparison on the QoS parameter of the QoSdata flow.

Optionally, in an embodiment, the receiving module 1710 is furtherconfigured to receive a first message sent by the CU, where the firstmessage includes the QoS parameter of the QoS data flow and/or themapping information between the QoS data flow and the bearer; and theprocessing module 1720 is specifically configured to establish thebearer between a DU and user equipment UE based on the first message.

Optionally, in an embodiment, the receiving module 1710 is furtherconfigured to receive a bearer modification message sent by the CU,where the bearer modification message includes at least one of firstinformation and second information, the first information is a modifiedQoS parameter of the bearer, and the second information is used to add aQoS data flow to the bearer or remove a QoS data flow from the bearer.

Optionally, in an embodiment, the mapping information between the QoSdata flow and the bearer is determined by the CU at a Service DataAdaptation Protocol SDAP layer.

Optionally, in an embodiment, the receiving module 1710 is furtherconfigured to receive a non-QoS-data-flow-level QoS parameter sent bythe CU, where the non-QoS-data-flow-level QoS parameter includes any oneof a slice-level QoS parameter, a UE-level QoS parameter, and a packetdata unit PDU session-level QoS parameter; and the processing module1720 is specifically configured to control, based on thenon-QoS-data-flow-level QoS parameter, data transmission of any one of aslice, a UE, and a PDU session.

FIG. 18 is a schematic block diagram of a terminal device 1800 accordingto an embodiment of this application. The terminal device 1800 includes:

an obtaining module 1810, configured to obtain mapping informationbetween a QoS data flow and a bearer, where the mapping information isdetermined by a CU based on a QoS parameter of the QoS data flow; and

a sending module 1820, configured to send uplink data to a DU based on amapping relationship between the QoS data flow and the bearer.

Optionally, in an embodiment, the obtaining module 1810 is specificallyconfigured to: receive a Radio Resource Control connectionreconfiguration message sent by the DU; and obtain the mappingrelationship between the QoS data flow and the bearer from the RadioResource Control connection reconfiguration message.

Optionally, in an embodiment, the terminal device 1800 further includes:a receiving module 1830, configured to receive a bearer modificationmessage sent by the DU, where the bearer modification message includesat least one of first information and second information, the firstinformation is a modified QoS parameter of the bearer, and the secondinformation is used to add a QoS data flow to the bearer or remove a QoSdata flow from the bearer; and a processing module 1840, configured todetermine the QoS parameter of the bearer based on the bearermodification message, and/or add a QoS data flow to the bearer or removea QoS data flow from the bearer based on the bearer modificationmessage.

An embodiment of this application further includes a base station. Thebase station includes the foregoing CU and DU.

It should be understood that the base station herein may be a basestation or a device having a similar function in various systems. Thebase station may also be an eNB in an LTE system, a gNB in a new radio(NR) system, a controller, or the like.

FIG. 19 is a schematic block diagram of a communications apparatus 1900according to an embodiment of this application. The communicationsapparatus 1900 includes:

a memory 1910, configured to store a program;

a processor 1920; and

a transceiver 1930, where when the program stored in the memory isexecuted by the processor 1920, the processor 1920 and the transceiver1930 can implement the processes in the foregoing communication methods.

A person of ordinary skill in the art may be aware that, in combinationwith the examples described in the embodiments disclosed in thisspecification, units and algorithm steps may be implemented byelectronic hardware or a combination of computer software and electronichardware. Whether the functions are performed by hardware or softwaredepends on particular applications and design constraints of thetechnical solutions. A person skilled in the art may use differentmethods to implement the described functions for each particularapplication, but it should not be considered that the implementationgoes beyond the scope of this application.

It may be clearly understood by a person skilled in the art that, forthe purpose of convenient and brief description, for a detailed workingprocess of the foregoing system, apparatus, and unit, reference may bemade to a corresponding process in the foregoing method embodiments, anddetails are not described herein again.

In the several embodiments provided in this application, it should beunderstood that the disclosed system, apparatus, and method may beimplemented in other manners. For example, the described apparatusembodiment is merely an example. For example, the unit division ismerely logical function division and may be other division in actualimplementation. For example, a plurality of units or components may becombined or integrated into another system, or some features may beignored or not performed. In addition, the displayed or discussed mutualcouplings or direct couplings or communication connections may beimplemented by using some interfaces. The indirect couplings orcommunication connections between the apparatuses or units may beimplemented in electrical, mechanical, or other forms.

The units described as separate parts may or may not be physicallyseparate, and parts displayed as units may or may not be physical units,may be located in one position, or may be distributed on a plurality ofnetwork units. Some or all of the units may be selected based on actualrequirements to achieve the objectives of the solutions of theembodiments.

In addition, functional units in the embodiments of this application maybe integrated into one processing unit, or each of the units may existalone physically, or two or more units are integrated into one unit.

When the functions are implemented in the form of a software functionalunit and sold or used as an independent product, the functions may bestored in a computer-readable storage medium. Based on such anunderstanding, the technical solutions of this application essentially,or the part contributing to the prior art, or some of the technicalsolutions may be implemented in a form of a software product. Thesoftware product is stored in a storage medium, and includes severalinstructions for instructing a computer device (which may be a personalcomputer, a server, a network device, or the like) to perform all orsome of the steps of the methods described in the embodiments of thisapplication. The foregoing storage medium includes: any medium that canstore program code, such as a USB flash drive, a removable hard disk, aread-only memory (ROM), a random access memory (RAM), a magnetic disk,or an optical disc.

The foregoing descriptions are merely specific implementations of thisapplication, but are not intended to limit the protection scope of thisapplication. Any variation or replacement readily figured out by aperson skilled in the art within the technical scope disclosed in thisapplication shall fall within the protection scope of this application.Therefore, the protection scope of this application shall be subject tothe protection scope of the claims.

What is claimed is:
 1. A communication method, comprising: obtaining, bya central unit (CU), a quality of service (QoS) parameter of a first QoSdata flow; performing, by the CU based on the QoS parameter of the firstQoS data flow, mapping between the first QoS data flow and a bearer toform a mapping relationship; determining, by the CU, a QoS parameter ofthe bearer based on the QoS parameter of the first QoS data flow;sending, by the CU, a context setup request message to a distributedunit (DU), wherein the context setup request message comprises the QoSparameter of the bearer, the QoS parameter of the first QoS data flowand the mapping relationship, the CU and the DU are comprised in a basestation, the context setup request message enables the DU to controldata transmission on the bearer based on the QoS parameter of thebearer; and sending, by the CU, a message for bearer modification to theDU, wherein the message for bearer modification comprises a firstinformation configured to add a second QoS data flow to the bearer. 2.The method according to claim 1, wherein the method further comprises:receiving, by the DU, the context setup request message from the CU. 3.The method according to claim 1, wherein the method further comprises:sending, by core network to the CU, a QoS data flow identifier (ID) anda mapping between the QoS data flow ID and the QoS parameter of thefirst QoS data flow.
 4. The method according to claim 3, wherein themethod further comprises: receiving, by the CU from the core network,the QoS data flow ID and the mapping.
 5. The method according to claim1, wherein the mapping between the first QoS data flow and the bearer isperformed by the CU at a service data adaptation protocol (SDAP) layer.6. The method according to claim 1, wherein the message for bearermodification further comprises second information configured to modifythe QoS parameter of the bearer.
 7. The method according to claim 1,wherein the method further comprises: receiving, by the DU, the messagefor bearer modification from the CU.
 8. The method according to claim 1,wherein the CU comprise s functions of packet data convergence protocol(PDCP), radio resource control (RRC) protocol, and service dataadaptation protocol (SDAP); and the DU comprises functions of radio linkcontrol (RLC) protocol, medium access control (MAC) protocol, and aphysical layer protocol.
 9. The method according to claim 1, wherein themethod further comprises: controlling, by the DU, data transmission onthe bearer based on the QoS parameter of the bearer.
 10. A communicationmethod, comprising: receiving, by a distributed unit (DU), a contextsetup request message from a central unit (CU), wherein the contextsetup request message comprises a quality of service (QoS) parameter ofa bearer, a QoS parameter of a first QoS data flow and a mappingrelationship between the first QoS data flow and the bearer, the CU andthe DU are comprised in a base station, the context setup requestmessage enables the DU to control data transmission on the bearer basedon the QoS parameter of the bearer; receive, by the DU, a message forbearer modification from the CU, wherein the message for bearermodification comprises a first information configured to add a secondQoS data flow to the bearer; and controlling, by the DU, datatransmission on the bearer based on the QoS parameter of the bearer. 11.The method according to claim 10, wherein the message for bearermodification further comprises second information configured to modifythe QoS parameter of the bearer.
 12. The method according to claim 10,wherein the CU comprises functions of packet data convergence protocol(PDCP), radio resource control (RRC) protocol, and service dataadaptation protocol (SDAP); and the DU comprises functions of radio linkcontrol (RLC) protocol, medium access control (MAC) protocol, and aphysical layer protocol.
 13. A communications system, comprising acentral unit (CU) and a distributed unit (DU), wherein the CU and the DUare comprised in a base station, and wherein the CU comprises at least afirst processor and a first non-transitory computer readable medium, thefirst non-transitory computer readable medium stores first programminginstructions, when executed by the at least the first processor, thefirst programming instructions instruct the CU to: obtain a quality ofservice (QoS) parameter of a first QoS data flow; perform, based on theQoS parameter of the first QoS data flow, mapping between the first QoSdata flow and a bearer to form a mapping relationship; determine a QoSparameter of the bearer based on the QoS parameter of the first QoS dataflow corresponding to the bearer; send a context setup request messageto the DU, wherein the context setup request message comprises the QoSparameter of the bearer, the QoS parameter of the first QoS data flowand the mapping relationship, the CU and the DU are included in a basestation, the context setup request message enables the DU to controldata transmission on the bearer based on the QoS parameter of thebearer; and send a message for bearer modification to the DU, whereinthe message for bearer modification comprises a first informationconfigured to add a second QoS data flow to the bearer.
 14. The systemaccording to claim 13, wherein the DU comprises at least a secondprocessor and a second non-transitory computer readable medium, thesecond non-transitory computer readable medium stores second programminginstructions, when executed by the at least the second processor, thesecond programming instructions instruct the DU to: receive the contextsetup request message from the CU.
 15. The system according to claim 13,wherein the system further comprises a core network, the core networkcomprises at least a third processor and a third non-transitory computerreadable medium, the third non-transitory computer readable mediumstores third programming instructions, when executed by the at least thethird processor, the third programming instructions instruct the corenetwork to: send to the CU a QoS data flow identifier (ID) and a mappingbetween the QoS data flow ID and the QoS parameter of the first QoS dataflow.
 16. The system according to claim 15, wherein the firstprogramming instructions further instruct the CU to: receive the QoSdata flow ID and the mapping from the core network.
 17. The systemaccording to claim 13, wherein the mapping between the first QoS dataflow and the bearer is performed by the CU at a service data adaptationprotocol (SDAP) layer.
 18. The system according to claim 13, wherein themessage for bearer modification further comprises second informationconfigured to modify the QoS parameter of the bearer.
 19. The systemaccording to claim 13, wherein the CU comprise s functions of packetdata convergence protocol (PDCP), radio resource control (RRC) protocol,and service data adaptation protocol (SDAP); and the DU comprisesfunctions of radio link control (RLC) protocol, medium access control(MAC) protocol, and a physical layer protocol.
 20. The system accordingto claim 14, wherein the second programming instructions furtherinstruct the DU to: control data transmission on the bearer based on theQoS parameter of the bearer.